The present invention relates to a shuttle motion assembly to be used in a data storage system. In particular, this application relates to a shuttle motion assembly which provides horizontal, vertical, and door-accessing movements to place the shuttle into, or out of, a proper operation position in a disk drive.
Data storage is an important aspect of today""s information technology. In order to meet the ever stronger demand for higher capacity storage devices, the areal data density of a storage medium has been increasing steadily. Various types of disks, including magnetic disks and optical disks, constitute recording media.
Magnetic storage devices such as fixed or removable magnetic A disks and tapes are widely-used conventional storage devices. The state-of-art conventional magnetic hard drive systems can achieve extremely high linear bit densities on the order of magnitude of about one gigabit per square inch. One limitation in increasing areal data density in a magnetic device is the particle size or the characteristic dimension of a typical magnetic domain of the magnetic recording materials. Other limitations include the width of the magnetic read/write head and the limitations of mechanical tracking. Therefore, these hard drives are typically limited to less than 10,000 tracks per inch.
Optical storage devices are emerging as an alternative technology to the conventional magnetic technology because of their potential for high density data storage. The areal density of an optical storage device, in principle, is only limited by the diffraction limit of an illuminating optical beam for reading or writing. One type of commercial optical storage technology is based on magneto-optical materials. These materials currently produce an areal data density of about one giga bits per square inch.
Data is generally stored in each disk in a series of concentric or spiral tracks. These tracks are accessed by one or more read/write heads in the head assembly. A head is mounted to an arm that is in turn mounted to the voice coil motor, such as a rotary voice coil actuator.
The disk and the head assembly are delicate mechanisms requiring protection. In order to protect against mechanical stress or contamination, a disk is sometimes designed to be inside a shuttle, which is then protected by a hard casing, or a cartridge. In such a design, when a disk is loaded into the disk drive, the cartridge is first removed, and the shuttle is then loaded into the disk drive.
During operation, it is necessary to move the head from a current position to a target track in an operation referred to as a xe2x80x9cseekxe2x80x9d operation. In such a seek operation, a command is provided to the data storage device to access a certain sector on the disk(s). If the head is not positioned over a target track containing the desired sector, a seek profile is determined. The seek profile contains various parameters associated with the head, including acceleration, deceleration, velocity and position information of the head. The seek profile is used to move the head from its current position to the target track by moving the head to the target track.
Once the head is positioned over the target track, the head is maintained over the target track""s center line for accurate read/write operations in an operation known as track following. A position error signal (PES) is generated based on variations of the head from the center line of the target track. The PES is part of a closed-loop servo drive system which obtains actual head position information based on a servo pattern and compares the servo pattern to the desired head position information. When the PES identifies a variation, the servo control system provides correction commands to the voice coil motor to accurately maintain the head over the center line of the target track.
The above paragraphs illustrates the need for repeatable, precise positioning of the disk inside a disk drive for information retrieval.
Because of the precise positioning required to read/write data from/to a disk, a loading mechanism to control the shuttle motion inside a disk drive is required. Moreover, the shuttle movements are best handled by an apparatus rather than by a user. Therefore, there is a need for an invention to provide a stand alone shuttle loading mechanism fitted in a disk drive to precisely place the shuttle inside the drive.
The advantages of this invention include one or more of the following:
This invention provides an easy-to-assemble, single-assembly shuttle motion assembly to perform several complex types of movements. In this mechanism, assemblies to control movements along a horizontal plane, a vertical plane, and door opening/closing motions are compactly assembled in one stand-alone unit. This unit provides repeatable, reliable positioning of the shuttle inside a disk drive.
Furthermore, putting the different motion assemblies into a stand-alone unit simplifies the task of assembling the disk drive, which has to perform many other complex functions. This stand-alone unit can be assembled separately then fitted into the disk drive.
Another advantage of this mechanism is that it is driven by a single motor and drive train. Yet another advantage of this mechanism is its use of circular cams to amplify a small radial movement into a relatively large linear movement.
In general in one aspect, the invention provides a shuttle motion assembly positioned in a disk drive to load and unload a shuttle. It includes a base plate, a plurality of cams positioned on the base plate, a hook positioned above the base plate to remove from a cartridge. A horizontal motion assembly is positioned on the base plate to create horizontal movement of the shuttle within the disk drive, a vertical motion assembly is positioned on the base plate to create vertical movement of the shuttle for mounting the disk contained in the shuttle on a spinning motor and, a shuttle-door accessing mechanism is positioned above the plurality of cams to open a door on the shuttle for accessing the recording media inside the shuttle.
Implementation of the invention may include the following. A horizontal motion assembly has a plurality of interconnected cams and levers. The horizontal motion assembly may include a plurality of channels in which the plurality of levers travel. The plurality of cams may be formed of plastic and may be radial cams. At least one cam of the plurality of cams may include recessed patterns on a top surface and a bottom surface, recessed patterns may be configured to move the shuttle inside the disk drive. The plurality of interconnected levers and cams may be metallic. The vertical-motion assembly may have a plate cam, with a recessed pattern for directing vertical movement of the shuttle. The shuttle-door accessing mechanism may consist of a plurality of levers, one of the levers may have a pin to engage an access hole located at a bottom surface of the shuttle. The access door may open circumferentially. The hook may be configured to reach inside the cartridge to pull the shuttle into the disk drive.
In another aspect, the invention is directed to a shuttle motion device positioned in a disk drive for loading/unloading a shuttle containing a disk into/out of the disk drive. The device has a base plate, and a horizontal motion assembly positioned on the plate to move the shuttle along a horizontal plane to place the shuttle into/out of the disk drive for engaging/disengaging a motor for spinning one or more recordable medium contained in the shuttle. The assembly has a plurality of circular cams and a plurality of channels for guiding a plurality of levers.
The implementation of the invention may include one or more of the following: a vertical motion assembly positioned on the base plate,with a lever and a cam plate, and a door-accessing mechanism to open an access door of the shuttle. The door-accessing mechanism may have a lever with an engagement pin to engage a door access hole on the shuttle, and a plurality of interconnected levers. Each circular cam may have a top surface and a bottom surface. Each surface may include grooved patterns to control a sequence of movements among the plurality of levers to effect movements of the shuttle. It may have a hook to pull the shuttle into the disk drive.
In another aspect, the invention is directed to a method of positioning a disk shuttle inside a disk drive. The method includes one or more of the following. Placing the shuttle at an entry door of the disk drive, moving the shuttle along a horizontal plane to place it over a motor inside the disk drive for spinning a disk contained inside the shuttle, lowering the shuttle along a vertical plane to mount the shuttle on the motor, and activating a door-access mechanism to open a door on the shuttle to expose the disk.
Implementations of the invention may include the step of removing the shuttle from a cartridge. The removing step may be conducted by a hook which latches to the shuttle. It may have a plurality of cams with recessed patterns to-position the shuttle inside the disk drive with repeatable precision. The plurality of cams and a plurality of levers connected thereto may constitute a motion amplification mechanism. It may provide a gear train and a motor to furnish movement power.